1. Field of the Invention
The present invention relates to an electrical junction box such as a fuse box, more particularly to an electrical junction box having a current sensor that includes both a ferrite bead and a Hall element.
2. Prior Art
A known electrical junction box having a current sensor is disclosed , for example, in Japanese Design Model Application Laid-open No. 64-42465.
FIG. 6 is a perspective view showing the known electrical junction box illustrated in the '465 Application. Furthermore, FIGS. 7A to 7C show a current detecting circuit provided in the electrical junction box, FIG. 7A being an exploded perspective view thereof, FIG. 7B a perspective view in the completely assembled condition, and FIG. 7C a sectional view of FIG. 7B.
Referring to FIG. 6, the electrical junction box (a main fuse box) 100 has a box 101 and a cover 102 both formed in a U-shape, in which there are disposed fuses 103, 104. For major electrical wiring in the box 101, there are disposed busbar strips 105 on a bottom surface of the box 101.
Further, adjacent to the main fuse 103 in the box 101 is arranged a current detecting circuit 106 that has been received in an exclusive case 110 (see FIG. 7A).
Next, referring to FIGS. 7A to 7C, the current detecting circuit 106 will be discussed.
In these figures, denoted 111 is a ferrite bead that is inserted in the case 110 to be located around a hollow pillar 110a. The ferrite bead 111 is formed with a cutout 111a into which a Hall element 112 is inserted upwardly in the case 110. The ferrite bead 111 and the Hall element 112 constitutes a current sensor that can detect a current flown in busbars 113, 114 (current detecting terminals) inserted into the hollow pillar 110a.
The busbars 113,114 connect respectively to power supplying cables 115,116. More specifically, the busbar 113 connects to a battery (not shown) by way of the cable 115 illustrated in FIG. 6, and the busbar 114 connects to various kinds of loads (not shown) by way of the cable 116 illustrated in FIG. 6 for detecting currents thereof.
Denoted 117 is an amplifier for amplifying a detected signal outputted from the Hall element 112. A connector 118 connects terminals including an output terminal of the Hall element 112 to a control unit (not shown). Further, denoted 119 is a fixing member for securing the ferrite bead 111 in the hollow pillar 110a.
However, in the aforementioned known electrical junction box 100, the busbars 113, 114 are connected respectively to the power supplying cables 115, 116, while the output terminal of the Hall element 112 must be connected to the control unit by way of the connector 118. Therefore, a more efficient connection device for the current detecting circuit 106 has been desired to reduce hand work.
In addition, it requires a lot of hand works to assemble the current detecting circuit 106 itself, since it includes relatively many element parts.
Moreover, the exclusive case 110 occupies a larger space in the electrical junction box 100, causing the electrical junction box 100 to enlarge in size.